A kind of semiconductor device with STI structure and preparation method

Abstract

The invention provides a semiconductor device with an STI structure and a preparation method. The preparation method is that a reflecting wall is formed in the STI structure while the STI structure is formed; the reflecting wall can stop light reflecting to photoresist to cause excessive exposure during performing subsequent photoetching process for the semiconductor device with the STI structure, thus the photoresist can be kept in good appearance all the time, and a device with an ideal appearance can be prepared; meanwhile, an anti-reflection layer for assisting photoetching is not needed, so that the production cost can be reduced.

Description

technical field [0001] The invention relates to the field of semiconductor preparation, in particular to a semiconductor device with an STI structure and a preparation method. Background technique [0002] In the preparation process of semiconductor chips, STI (Shallow Trench Isolation, shallow trench isolation) plays a pivotal role. Because it can achieve high-density isolation, it is widely used in deep submicron devices and DRAM (Dynamic Random Access Memory, dynamic random access memory), etc. Manufacturing of high-density memory circuits, but as the critical dimensions of devices continue to shrink, problems also emerge. [0003] In some STI manufacturing processes, the side walls that make up the STI are generally inclined walls. At the same time, in the semiconductor manufacturing process, a complete process may require dozens of photolithography processes, such as the first patterning process to form After STI, another subsequent patterning process is required to pe...

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Problems solved by technology

In the prior art, a layer of anti-reflection layer is generally pre-coated on the bottom of the photoresist to reduce the impact of light reflection on the photoresist, but its cost is relatively high, and it contains ion implantation. Not applicable in the process: In some ion implantation processes, it is necessary to use the remaining photoresist as a mask to perform an ion process on a specific area, but because the anti-reflection layer will form a blocking effect on the implanted ions, which will affect the implantation Effect

In order to solve the limitations of the traditional anti-reflection layer in the process, a relatively advanced anti-reflection layer has been developed. This anti-reflection layer has less impact on ion implantation, but the cost of using the anti-reflection layer is very high, which also increases production. cost

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